Core-sampling tool



Feb. 17, 1953 I R MAHAN 2,628,816

CORE-SAMPLING TOOL .3 Sheets-Sheet 1 Filed Aug. 20, 1949 A YMO/VO MAHAN B 6' a ttomeg Feb. I7, 1953 Rfl. MAHAN CORE-SAMPLING TOOL 3 Sheets-Sheet 2 Filgd Aug. 20, 1949 Cittorneg RA YMOA/O MAHAA/ a 4. 5%

Feb. 17, 1953 V R. MAHAN CCRE-SAMPLING TOOL "Med Aug. 20, 1949 3 Sheets-Sheet 5 Patented Feb. 17, 1953 UNITED STATES PATENT OFFICE Raymond I. Mahan, Long Beach, Calif. Application-Aug ust 20, 1949, Serial No. 111,371

T is invention relates to a tool that is adapted to be run into a well bore or the like for the purpose of removing a sample core from the bottom ofthe bore. v 1 i The primary object of the invention is to provide a tool, as indicated, that extracts a sample core which is so oriented with the cardinal points of the compass that the formation, the angle, and the direction of angle of the bedding layers thereof can be readily determined.

Another object of the invention is to provide a core-sampling tool that is adapted to have a diametral size enabling runningthe same to the bottom of a hole through the bore of a string of drill pipe or through casing, said tool, of course,

"being adapted to be run into an open hole.

Another object ofthe invention is to provide an oriented core-sampling tool that provides a record of the relationship of the orientation mark on the sample core and the cardinal points of the compass, and also, if any, of the degree of inclination of the well bore and the direction of said inclination with respect to the compass.

, A further object of the invention is to provide a tool, as indicated, that embodies novel impact means of taking the sample core, the same being automatic upon engagement of the end of the tool with the bottom of the well bore.

' A further objectof the invention is to provide a core-sampling tool adapted to be run down through the axial bore of a drill string and beyond the bit on the end of said string and to so 'co-act with said bit as to receive the full weight of the drill strin whereby said tool, under force of. said weight, is pressed into the formationat the bottom of, a well hole, J

. flheinvention alsohasfor its objects to pro,- vide such means that are positive in operation, convenient in .use, easily installed in a working position and easily disconnected therefrom, economical of manufacture, relatively simple, and of general superiority and serviceability.

The invention also comprises novel details of construction and novel combinations and arrangements of parts, Which will more fully appear in the course of the following description. However, the drawings merely show and the followingdescription merely describes embodiments of the present invention, which are given by way of illustration or example only.

Fig. 1 is a small scale elevational View, partly broken,showing a core-sampling tool accordin to the present invention.

Fig; 2is an enlarged schematic view of the preferred form of orienting recording section of said. tool.

- 3 Claims. (01. 255 1.4)

' Fig. 3 is a further enlarged face view of a record produced in the orienting recordingsection';

Fig. 4 is a perspectiveview 'of ajsample'jcore and indicating how" the same maybe associated with a compass-point-marked card or sheet to re-orient said core with the cardinal points of the compass so as to have a visual revelation of the angle and direction of angle of the bedding formation at the bottom of the bore from which said core is taken. 7

Fig. 5 is a longitudinal sectional view of .one form of sample-taking-impact section before the same is tripped. r 1

Fig. 6 is a similar view of'said section after tripping and taking of a sample core.-

Fig. 7 is an enlarged cross-sectional taken on line 'I 1 of Fig.5.

Fig. 8 is a longitudinalsectional view showing a modification of the'lower end of the impact section before the same is operated.

Fig. 9 is a similar view of said section after operation.

Fig. 10 is a longitudinal sectional view of the lower end of a well-drilling bit and a third form of sample-takingtool in operative combination.

Fig. 11 is an enlarged longtiudinal and partly broken sectional view of the tool shown in Fig. 1 in the condition the parts assume during passage through the drill bit and its string.

Figs. 12 and 13 are cross-sectional views as taken on the respective lines l2-l2 and l3--l3 of Fig. 11.

, The tool that is shown in Fig. 1 comprises four essentialsections, a loading section A, a jars section B, an orienting and recording section 0, and an impact and core-taking section D, arranged one below the other in'the'order named and suspended from a cable or wire In whereby said tool is lowered into a well bore either-in an open hole, through a lining casing, orthrough a drilling string, as the case may be. V

The loading section A may be of any suitable lengt and, so that the same may have suflicient weight for operating the impact section D, is preferably comprised of sections of tubing and/or sinker bars sufi'icient in number to provide the desired weight.

The jars section B may be generally conventional and is provided primarily to insure careful withdrawal of the tool from the hole after the sample core is taken. Instead of an inordinately strong pull, by means of the jars, short upward tugs on cable I 0 will result in progressive taps that will loosen the core in a safe and'careful manner. I

The orienting and recording section 0 may be view as any of the well known time or gravity actuated mechanisms if the hole has appreciable inclination, or a magnetic directional surveying device if the hole has less than two degrees of inclination. Section C, per se, does not constitute a part of the present invention. However, such a section, in operative combination with all or some of the other sections of the tool, contemplates one novel phase of the present tool.

Figs. 2 and 3, for reasons of clarity, illustrate the essential features of a preferred form of orienting and recording section. As shown in the schematic form of Fig. 2, said section comprises a timer, such as a time clock II, a, source of power such as dry cell batteries [2, a light source [3, camera means It, a magnet l5 adapted to be photographed by the camera on a card It, a suitable optical system l1, an inclination indicating ring it, and an orientation point, or index 19, said camera being adapted to also photograph said ring andindex on card It. As atresult, card i6. which is initially blank, but light sensitive, has photographed thereon compass marks 20, a series of concentric rings 2! representing one degree angles of inclination relative to the center of the card, an image 22 otindex I9,and an image 23 of ring I8. It is immaterial at what angular disposition index [3 is with respect to the cardinal points of the compass I'5 since the latter constitutes a fixed reference by means of which the angular position. of index I9 is determined. In the example shown in Fig. 3, the image 22 of index 19 is shown at 21F; of S.

Any inclination of the hole is shown by image iii-which will fall oif the center since ring I8 is freely suspended. As shown, the inclination on the example is some three and one-half degrees and the direction of the inclination is 44 E. of N. Any time after the sample is taken by operation of the impact. section, section C may simultaneously record the above-outlined orientationof the toolrelativeto the compass, and the angle and direction of the hole.

As: indicated, the above-described orientation section C may vary. The one described will provide all the needed information regarding the angle and orientation of the hole. In instance where some of this information is already known, section C may incorporate only such means as will complete the needed information.

The impact and core-taking section D that is shown in Figs. 5, 6 and *1 comprises an outer tube 24. which is provided with a key 25 engaged in aslot 26 an extension 21 of section C. Thus, sections 0. and D. are held against relative rot; nwhile they may move relatively longitudinally. The bottom of tube 24. is provided with a fitting 28 adapted to.- engage the: bottom of the holeZ-Q, while the tool is. being lowered and enabling the weight of section, A to further depress extension 21 and a hollow barrel 30 threadedl-y connected to said extension at 3!. Said barrel has a bottom wall 32 which constitutes the upper abutment for a compression spring 33.

The. lower abutment for said spring comprises a providing that. flange. 34. is held against downward movement.

To this end, the flange 34 is affixed to a ram or percussion element 38 which is locked in place as by, at least, two detent balls 39 in transverse passages ii] in said ram, said balls engaging in hardened seats M provided in tube 24 and retained therein by plug 35. A coil spring 42 normally supports said plug so that the same retains a position between the balls whereby the ram 38. is. locked and the. spring 33 is enabled to be compressed, as above indicated.

The first portion of the downward movement of barrel 3!! stores energy in spring 33. Then, as this movement continues, the bottom face 43 of extension 21 engages head 31 to move stem 36 and plug 35 down against the light force of spring 42. Said plug will thus be removed from between the balls 39. The force of spring 33 is now enabled to urge said balls inwardly out of. their seats M to, thereby, free the ram 38, which, under power from spring 33, is propelled downward with considerable force.

Below the ram 38 and guided in tube 24, there is provided a unit that comprises a piston 84 that is adapted to be struck by the ram, and a core-taking tube 45 removably connected to said piston. Said tube 45 is guided in fitting 28 and is adapted to be retracted thereinto as in Fig. 5.

According to the present invention, tube 45 is non-rotationally held in tube 24 by a-key projection at thereon and a key slot 47. Also, the bore 158 of tube 45, at or near its bottom end, is provided with a correlating device such as a knifelike projection 49 or anything that will similarly mark or scribe a core sample 50 with a longitudinal mark, line, etc. 5| when the force of ram 38 has projected tube 45 into the bottom 29 as indicated in Fig. 6.

While key .46 and keyway 4! need not have any special orientation with index [9, projection 59 is so positioned as to be exactly aligned with said index or at a known angle thereto so that definite relationship between the index and the projection is known. Said key and keyway insure retention of such correlation.

The taking of the core sample is automatic, since only continued lowering of the tool is all that is necessary to first bottom the tool, then release the ram, and finally project the core tube into the bottom.

When the tool is to be extracted from the hole, the first pull on cable II] will. cause wall 32 to engage head 31 and exert a lift on ram 38 by means of. the interengagement of plug 35 and balls 39. This lift. continues until said balls arrive opposite seats. 41 and fall thereinto releasing the plug. for further upward movement while. looking the ram. "Ifhen, as barrel, 30 engages. stop abutment 52 carried by tube 24, an upward force. isv imp rted to. the latter. Since tube is. firmly imbedded. in the. formation of hole bottom 2.9,v the jars section now becomes efiective to gently create a series of. removal taps, by alternately slacking off and pulling on cable 10... When the tool is. completely withdrawn, fitting 28. is. removed so that tube 45 and its piston can be extracted from tube. 24. Now, said tube. and piston can be separated and the sample core 50 of the formation pushed out of the former.

Of. course, removal of the tooldestroys any relationship that the core had with the well bottom, but. such relationship is readily re-established by consulting the. record on card'lfi, since the line 5| on said core was coordinated with image 22 when the core was taken. It will be evident that the strata. of the core 58 as indicated by lines 53-, when said core'is associated with a compass card, as, in Fig. 4, so that line has the same relationship thereto as has index image 22, are. reoriented, with the points of the compass. Now, the angle and the direction of the strata can readily be determined to give geological inlar to that shown in Figs. 5 and 6. Said piston is sealed to, retain the expanding gases of explosion by O-rings 51. Here, also, tube 45 is held against rotation relative to tube 24. In addition,

said tube is provided with an outwardly directed projection 58' that cuts, a line or groove 59' in a copper or other soft metal ring 60 through which the tube moves when propelled. This line 59 may;

that portion of bore 12 that is formed in bit llbe used to check the initial correlation with index f l9 and if f such correlation has been disturbed during operation, a suitable correcting factor would be introduced in the angular dimension 6| (Fig. 4). r r

Since the forces of explosive 54 are equal in all directions, the modification preferably entails terminating tube 24 short of the end of section D and housing the above-described elements in a strong unit 82 capable of withstanding the forces of explosion.

Since the tool may be lowered into water or other fluid, displacement of the. same is afforded through openings 63 in tube 24. "Also, air cushions are, 1 thereby, eliminated.

Since section C depends for its proper function on the magnetic position of magnet l5, the barrel ,64 lther'efor is made of a non-magnetic metal" so as riot t'o'interfere with said magnet. K-Monel has been found satisfactory for this purpose.

The modification of Figs. 10 to 13 contemplates utilizing the weight of a drilling string, rather than an impact, for embedding the core-taking tube 45 in the bottom 29 of the hole. Such a tool may be used where the formation is sufficiently penetrable bysuch a weight. 1 Fig. 10 illustrates a conventional hole-boring bit 10 connected on the lower end of a drilling M string 1!. In the usual manner, a longitudinal passage 12 extends through the string and bit,

being normally used for passing flushing fluid down into the hole. Bit I8 is provided witha stop or slush ring 69, the same constituting a shoulder ius'eid for other purposes. T Insteadof section D, above described as and pact section, the present modification compf v a sectionD -designed for'operative inter-engagement with bit 10 to utilize the weight of said bit and of the drill string H. e;- The upper end of section D comprises a fitting I3 removably aifixed to the lower end of section 0. A lower extension 14, of smaller diameter than said fitting, extends downward and terminates in a plunger 15, there being a shoulder, 16 where extension 14 and plunger 15 meet. The lower end of section D comprises an elongated unit 11 which, near its upper end, is provided with an enlarged shoulder 18 of a diametral size to freely move in passage 12.

Unit 11, above shoulder 18, is provided with a bore 19 for extension 14 and a key 80 is provided to hold said extension and unit 11 against relative rotation while onemoves axially relative to the other. Bore 19 terminates in an internal shoulder 8| for shoulder 18 of plunger I5 and,

below shoulder 8|, a bore 82 to telescopically ac commodate said plunger, is provided.

Intermediate shoulder I8 and the lower end of unit 11, the latter mounts at least two opposed.

or, as shown, two pairs of opposed dogs 89 that are hinged to unit 11 at their bottom ends, as on pins 84 and extend upward in slots 85 provided in said unit. Each dog, at its upper end, is provided with an outer downwardly and outwardly sloping edge 86 and with an? inner opposed convexly curved edge 81. The upper ends 88 of said dogs'are retained by abutments 89 from com-' I Tube 45 is carried by the lower end of unit 11 in a manner, comparable to that describedin the earlier forms of the invention V I When a sample core is to be taken by a e561 embodying section D drill string H is lifted to raise bit 10 from the bottom 29 of the hole a distance somewhat greater than the distance .between dog ends 88 and the lower end of tube 45.

The tool is then lowered throughbore.12. If,

during the lowering, dogs 83 fall outward, it is immaterial since said dogs trail and will merely slide along the wall of bore 12. During thiscon- 'dition (Fig. 11) plunger'l5 is retracted since unit 11 is suspended from shoulder 16. .i

When shoulder 18 encounters stop :or..slush ring 69, the downward movementof unit 11 is arrested but with assurance that dogs 83 are now wholly below the lowermost part of bit '10. Lowering of the tool, except unit 11, continues until fitting 13 abuts the upper end of said unit. This last portion of the tool movement brought plunger 15 down into bore 82 and between the opposite edges 81 of dogs 8i! tohold said dogs outwardly projected. At this time, the bottomof tube 45 is still above the hole bottom 29.

Now, both the drill string II and the tool are lowered together. 'When tube 45 encounters the hole bottom 29, this downward movement of unit 11 is arrested. The drill string continues down effecting separation of shoulder 18 and stop ring 69. Then, as the bottom of bit 10 engages the outwardly projected sloping edges 86 of dogs 83, the entire weight of the drill string and bit is borne by unit 11. This great weight of many tons is sufflcient to cause tubejs to penetrate into the bottom formation 29 oflthe well bore. Since unit 11 is keyed to fitting |3 and the latter fixed, although removably, to section C, projection 49 of said tube will be oriented radially with the instrumentalities within said section as hereinabove described. 1

Removal of the tool is simple. String H is just lifted off the dogs and shoulder 18 used to dislodge tube 45 from the bottom formation. Then, the tool is raised to; effect withdrawal of plunger 15 from between ,the dogs. After shoulders 76 and 8| are re-engaged, the tool can be drawn to the surface, edges' 86 of the dogs merely camming inward past the abutments formed by the lower end of the bit and the bottom face of stop ring 89.

In this form of the invention, the jar section B is unneeded and may be omitted, since the drill string is used instead for dislodging the tool.

While the invention thathas been illustrated and described is now regarded as the preferred embodiments, the construction is, of course, subjeot to modifications without departing from the spirit and scope of the invention. It is therefore not desired to restrict the invention to the particular forms. ofconstruction illustrated and described, but to cover all modifications that may fall within the scope of the appended claims.

Having thus described the invention, what is claimed and desired to be secured by Letters Patent is:

1. A core-sampling tool comprising two telescop i c. units one above the other, the lower of said units having an axial bore, a plunger carried by the upper unit and movable therewith in said bore upon telescopic movement of the units, a set of upwardly directed dogs carried by said lower unit and pivotallyconnected at; their lower ends to saidrlower unit and having upper weight-bear-- ing shoulders said set of dogairora a normal position retracted on their pivots within the outer surface'of'the lower unit and, in part, within the mentioned bore of said unit, being adapted to be moved by the mentioned plunger to a projected position wherein said shoulders are beyond the outersurface of said lower unit, and a sampletaking tube carried by said lower unit at the lower end thereof and impressible into a hole formation upon weighting of said dog shoulders, said shoulders of the set of does being outwardiy anddownwardly sloped from their upper ends to constitute cams which, when weighted, urge said set of dogs to move to retracted position upon Withdrawal of the plunger from between them.

- 2. A core-sampling tool for operative engagement within the axial passage of a boring bit on the lower end of a drill string, there being an upwardly facing abutment in said passage, said tool comprising two telescopic units one above the other slidingly extending in said passage, the lower of said units having an axial bore, a plunger carried by the upper unit and. movable therewith in said bore upon telescopic movement of the units, a set of upwardly directed dogs carried by said lower unit adjacent the lower end thereof and pivotally connected at their lower ends to said lower unit and having upper shoulders adapted to be engaged by the lower end of. the bit and to bear the weight of said bit and drill string, said set of dogs, from a retracted position within the passage in the bit and, in part, within the bore of the lower unit, being adapted to be moved by the mentioned plunger to a projected position engaged by the lower end of the bit, a sample-taking member extending from the lower end of the lower unit and impressible into a hole formation formed by said bit by the weight of they bit and drill string on said set of dogs, and a downwardly facing abutment on said lower unit and spaced above the upper ends of the set of dogs to be above the upwardly facing abutment .in said passage, the spacing between the abutment on the lower unit and the set of dogs being such that,"

REFERENCES CITED The following references are of record in the file of this patent:

v UNITED STATES PATENTS Number 

